Corporate tax instalment calculator
Updated
Quick answer: Instalments catch profitable second-year corporations by surprise. Enter your tax owing to see whether they apply to you.
The first instalment year is the one that catches people, because the prior year’s tax was nil. Ask whether yours apply.
Opens your own email app with the numbers filled in — add your question and a CPA replies, usually the same business day.
General estimates, not tax advice. Rules change and your result depends on details a calculator cannot see; we confirm the numbers once we review your enquiry.
Nothing you type here leaves your browser. This calculator runs entirely on your device — no figures are sent to us or to anyone else.
Does my corporation have to pay tax instalments, and roughly how much per period?
Corporations past their first profitable year — the year the requirement usually appears without warning. It uses the prior-year method. The CRA allows three methods and you may use whichever is lowest, provided your estimate holds up.
On this page
A worked example
The calculator above uses these figures. It is not a CRA calculator, so treat the result as an estimate to confirm against your own figures.
| Step | Figure |
|---|---|
| Net federal tax | $12,000 |
| Threshold | Instalments generally required above $3,000 |
| Frequency | Quarterly, for an eligible small CCPC |
| Each instalment | $12,000 ÷ 4 = $3,000 per quarter |
| If not eligible for quarterly | Twelve monthly instalments of $1,000 instead |
What it assumes, and where it stops
Every estimate rests on assumptions. These are the ones that would change your number most.
| Assumption | What it means for your number |
|---|---|
| The prior-year method | Last year’s tax spread evenly. The current-year and two-year blended methods can be lower — but under-estimating creates instalment interest. |
| The threshold looks back two years | Instalments are required if net tax exceeded $3,000 this year OR in either of the two preceding years. One strong year can trigger them for the next. |
| First-year corporations are exempt | Which is exactly why year two surprises people: the first instalments can fall due in the same months you are paying year one’s balance. |
| Instalment interest is not deductible | Unlike most interest a business pays, this is a pure cost. |
General information, not advice. Have a CPA confirm it for your situation
The year-two surprise
A corporation pays no instalments in its first tax year. After a profitable year one, the CRA expects instalments through year two while you pay year one’s balance. Unbudgeted, that overlap feels like a tax increase; it is the same tax, paid earlier.
Three ways to calculate — pick the lowest
The CRA permits the prior-year method (last year’s tax, spread evenly), the current-year method (your estimate) and a two-year blended method. Use the smallest, but underestimate and non-deductible interest applies to the shortfall. Current-year suits a shrinking business. The corporation tax calculator above applies the prior-year method, so it shows the safe default rather than the lowest possible instalment.
If you have already missed some
Instalment interest is charged, but it can be offset by paying later instalments early — the CRA applies a contra-interest calculation. Catching up promptly genuinely reduces the cost. The full instalment guide or see the check when your corporate return is due for your filing and balance dates.
Free to use on your own site — the snippet keeps a credit link back to this page.
Corporate Tax Instalment Calculator FAQ
When does a corporation have to pay tax instalments?+
Monthly or quarterly?+
What if I pay too little?+
Do provincial instalments work the same way?+
How should I read the instalment amount this calculator gives me?+
What does the instalment calculator not account for?+
When should I have my instalment plan reviewed?+
If cash cannot cover these instalments, a CRA payment arrangement usually beats missing them; the guide explains arrears interest and negotiation. If the year-end is the problem, a year-end email course paces the close.
Related reading
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Instalments sit alongside your filing and balance-due dates. See how the corporate deadlines fit together.